KR20070058443A - Transfer belt for image-forming device - Google Patents

Abstract

Disclosed is a multilayer transfer belt for image-forming devices comprising a base layer (11), an elastic layer (intermediate layer) (12) and a surface layer (9) which has high surface resistivity, excellent toner releasability and excellent antifouling properties. The transfer belt for image-forming devices is characterized in that an elastic layer (12) containing an elastomer and a surface layer (9) composed of a fluorine-containing polymer are arranged on a base layer (11). The elastic layer (12) is preferably made of an ion conductive elastomer. Also disclosed is a transfer belt for image-forming devices further comprising a binder layer (14) between the elastic layer (12) and the surface layer (9) which is characterized in that the melting point of the material constituting the binder layer (14) is not more than the thermal decomposition point of the material constituting the elastic layer (12) and the thermal decomposition point of the material constituting the binder layer (14) is not less than the melting point of the material constituting the surface layer (9).

Description

Transfer belt for image forming apparatus {TRANSFER BELT FOR IMAGE-FORMING DEVICE}

BACKGROUND OF THE INVENTION Field of the Invention [0001] The present invention relates to an image forming apparatus using an electrophotographic method, particularly a color image forming apparatus such as a color copying machine or a color laser printer, which is used to transfer a toner image on a photosensitive drum onto a transfer material (paper). A transfer belt for an image forming apparatus

As a method of transferring images in color image forming apparatuses such as color copiers and color laser printers, a method of transferring a toner image formed on a photosensitive drum to a transfer material (paper) using a transfer belt for an image forming apparatus is standard. Is done by enemy.

7 is an explanatory diagram showing an outline of an intermediate transfer method that is one of these systems. As shown in FIG. 7, the toner image is formed on the photosensitive drum 3 by the toner 1 and the developing roller 2. Since this system is a four tandem system, four toners, a developing roller and a photosensitive drum corresponding to each of them are formed. The toner image formed on the photosensitive drum 3 is transferred to the transfer belt 5 for the image forming apparatus by the primary transfer roller 4, the photosensitive drum 3, and the transfer belt 5 for the image forming apparatus. . The formed color image is transferred to the transfer material (paper) 7 by the secondary transfer roller 6, the transfer belt 5 for the image forming apparatus, and the transfer material (paper) 7, and the fixing roller. (Not shown). Even in the case of the multiple transfer method, the basic principle is the same.

The transfer belt for the image forming apparatus used in these methods has a large resistivity (surface resistivity) in the circumferential direction of the belt, and a resistivity (volume resistivity) in the thickness direction smaller than the surface resistivity, and these resistivities are on the belt surface. Not to be changed by position, usage environment, voltage, etc., high elastic modulus of elasticity in the circumferential direction of the belt, smooth surface and large contact angle, making it easy to transfer toner from the belt to the transfer material (paper) (excellent peeling toner) Characteristics), such as not chemically contaminating the photosensitive drum, toner, etc. (excellent non-polluting), flame retardant, etc. are desired.

Since it is difficult to satisfy many of these characteristics by a single-layer transfer belt for an image forming apparatus, a transfer belt for an image forming apparatus having a multilayer is proposed. For example, Japanese Laid-Open Patent Publication No. 2002-287531, A transfer belt for an image forming apparatus is disclosed, which has a base layer of a low resistance thermoplastic elastomer and a surface layer of a high resistance thermoplastic elastomer, wherein the base layer and the surface layer are formed by heat molding.

Moreover, recently, a transfer belt for an image forming apparatus having elasticity in the thickness direction has also been desired. As a transfer belt for an image forming apparatus that satisfies this property, it is formed by an elastic body in addition to the base layer and the surface layer as described above. It is also conceivable to have an elastic layer (intermediate layer) to be used.

In the multilayer transfer belt for image forming apparatuses, the high tensile modulus in the circumferential direction of the belt is achieved by the base layer, and the elasticity in the thickness direction is achieved by the elastic layer. On the other hand, the stable volume resistivity is controlled by the selection of the material for forming the base layer and the elastic layer. Moreover, it is desired that large surface resistivity, excellent peeling toner property, and excellent non-pollution property are achieved by the surface layer.

However, conventionally, a transfer belt for an image forming apparatus that satisfies these characteristics has not been obtained.

[Patent Document 1]

Japanese Patent Application Laid-Open No. 2002-287531 (Claim 1)

1 is a cross-sectional view showing an example of a transfer belt for an image forming apparatus of the present invention;

2 is a view showing an example of a method of manufacturing a transfer belt for an image forming apparatus of the present invention;

3 is a view showing an example of a method of manufacturing a transfer belt for an image forming apparatus of the present invention;

4 is a view showing an example of a method of manufacturing a transfer belt for an image forming apparatus of the present invention;

5 is a view showing an example of a method of manufacturing a transfer belt for an image forming apparatus of the present invention;

6 is a cross-sectional view showing an example of a transfer belt for an image forming apparatus of the present invention;

7 is an explanatory diagram showing an outline of an image transfer method in which a transfer belt for an image forming apparatus is used.

<Description of the symbols for the main parts of the drawings>

1: toner 2: developing roller

3: photosensitive drum 4: 1st transfer roller

5: Transfer belt for image forming apparatus 6: Secondary transfer roller

7: transfer material 8: outer tube

9: surface layer 10: drum-shaped mold

11: base layer 12: elastic layer

13: middle 14: binder layer

The present invention provides a transfer belt for an image forming apparatus, which is a multilayer, having a base layer, an elastic layer (intermediate layer), and a surface layer, which has a large surface resistivity, excellent peeling toner property, excellent non-pollution property, and the like. Let that be the task. The inventor has found that this problem is achieved by forming the surface layer with a fluorine-containing polymer.

Another object of the present invention is to provide a transfer belt for an image forming apparatus having the above-described configuration and excellent features, and a transfer belt for an image forming apparatus having a stable volume resistance value and the like. The present inventors have found that this problem is achieved by forming the surface layer with a fluorine-containing polymer and forming an elastic layer formed by the ion-conducted elastomer between the base layer and the surface layer.

In the above invention, adhesion between the fluorine-containing polymer constituting the surface layer and the elastomer such as urethane constituting the elastic layer is generally carried out by physical treatment such as plasma treatment, blasting, or primer treatment. However, the former may require excessive effort and time, and may become expensive. In the latter case, contaminants may bleed through a thin surface layer.

The present invention also provides a transfer belt for an image forming apparatus having the above-described configuration and excellent features, which does not require excessive effort and time, and does not cause the problem of bleeding of contaminants. Another object of the present invention is to provide a transfer belt for an image forming apparatus in which excellent adhesion to a layer is secured. The present inventors have found that the above problem is achieved by forming a specific binder layer between a surface layer formed of a fluorine-containing polymer and an elastic layer formed of an elastomer.

This invention is completed based on these findings discovered as a result of earnestly examining.

Claim 1 of the present invention,

On the base layer,

An elastic layer having an elastomer,

Surface layer formed by fluorine-containing polymer

It is to provide a transfer belt for an image forming apparatus having a.

Since the surface layer of the transfer belt for image forming apparatus is formed of a fluorine-containing polymer, a large surface resistivity, excellent peeling toner property, excellent non-pollution property, and the like can be achieved. The present invention also provides a transfer belt for an image forming apparatus, which has a configuration shown below as a preferred embodiment.

A transfer belt for an image forming apparatus according to claim 1, wherein the elastic layer is formed of an ion-conducted elastomer (claim 2). The transfer belt for an image forming apparatus of this constitution has an excellent feature with a stable volume resistance value in addition to the above excellent features.

A transfer belt for an image forming apparatus according to claim 1, further comprising a binder layer between the elastic layer and the surface layer, the binder layer having a melting point of less than or equal to the thermal decomposition point of the material constituting the elastic layer, and a thermal decomposition point. And a transfer belt (claim 3), which is formed of a material having a melting point higher than that of the material forming the surface layer. According to the transfer belt for the image forming apparatus of this configuration, no excessive effort and time are required, and no problem of bleeding of contaminants can occur, and excellent adhesion between the surface layer and the elastic layer is secured.

As a material for forming the surface layer of the transfer belt for an image forming apparatus, in order to obtain excellent peeling toner, it is desired to have a large contact angle and to have high smoothness, but in the present invention, the fluorine-containing polymer for forming the surface layer is desired. To satisfy.

Among them, polytetrafluoroethylene (hereinafter referred to as PTFE) and tetrafluoroethylene perfluoroalkyl vinyl ether (hereinafter referred to as PFA) have a large contact angle and can remove the deposits of toner and the like cleanly. desirable.

Claim 4 of this invention corresponds to this preferable aspect, Comprising: The said transfer belt for image forming apparatuses is a transfer belt for image forming apparatuses characterized by the fluorine-containing polymer being PTFE or PFA.

As a fluorine-containing polymer which forms a surface layer, the polymer and copolymer of monomers, such as vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, tetrafluoropropylene, and hexafluoropropylene, are also illustrated. Among them, a polymer of a monomer containing vinylidene fluoride, that is, a homopolymer of vinylidene fluoride (polyvinylidene fluoride, hereinafter referred to as PVDF) or a copolymer of two or more monomers containing vinylidene fluoride Is preferably illustrated. They are also rich in flexibility and have the advantage of being difficult to impair the elasticity of the elastic layer.

Claim 5 of this invention corresponds to this preferable aspect, The transfer belt for image forming apparatuses characterized by the above-mentioned transfer belt for image forming apparatuss, The fluorine-containing polymer is a polymer of the monomer containing vinylidene fluoride. To provide.

Among the polymers of the monomer containing vinylidene fluoride, PVDF is preferable because the contact angle is large. In addition, PVDF can be annealed (sintered) at a temperature (about 160 ° C) that has a relatively low melting point and does not deteriorate an elastic layer such as urethane (decomposition temperature of about 170 ° C) among fluorine-containing polymers. In many cases, it has the advantage that the peeling toner property can be improved as a result.

Claim 6 of this invention corresponds to this preferable aspect, It is providing the transfer belt for image forming apparatuses as said transfer belt for image forming apparatuses, A fluorine-containing polymer is PVDF.

Among the polymers of vinylidene fluoride-containing monomers, copolymers of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride (hereinafter referred to as THV) have particularly large contact angles and very little bleeding. Non-pollution property is also especially excellent and it is especially preferable.

In addition, like PVDF, THV is annealed (sintered) at a temperature (about 160 ° C) that has a relatively low melting point and does not deteriorate an elastic layer such as urethane (decomposition temperature of about 170 ° C) among fluorine-containing polymers. In many cases, it has the advantage that the peeling toner property can be improved as a result.

Claim 7 of this invention corresponds to this preferable aspect, It is providing the transfer belt for image forming apparatuses as said transfer belt for image forming apparatuses, A fluorine-containing polymer is THV.

When THV or PVDF is used as the fluorine-containing polymer, and the elastic layer is formed of urethane, the surface layer is preferably simply formed by spray coating a solution of THV or PVDF onto the elastic layer.

Claim 8 of this invention corresponds to this preferable aspect, Comprising: As said transfer belt for image forming apparatuses, a fluorine-containing polymer is THV or PVDF, an elastic layer is urethane, and a surface layer is a solution of THV or PVDF. It is to provide a transfer belt for an image forming apparatus, characterized in that formed by spray coating on the elastic layer.

It is preferable that the thickness of a surface layer is the range of 1-15 micrometers. The same applies to the case where the transfer belt for the image forming apparatus has a layer other than the base layer, the elastic layer, the binder layer and the surface layer. If it is this range, sufficient wear resistance and flexibility can be made compatible.

Claim 19 corresponds to this preferred aspect, and provides a transfer belt for an image forming apparatus, wherein the thickness of the surface layer is 1 to 15 µm as the transfer belt for the image forming apparatus.

The elastic layer plays a role of imparting flexibility in the thickness direction of the belt. The transfer belt for an image forming apparatus of the present invention has sufficient flexibility in the thickness direction because an elastic layer formed of an elastomer is formed between the base layer and the surface layer. The elasticity that cannot be obtained in the conventional single-layer transfer belt for image forming apparatus allows the transfer belt for image forming apparatus to be transported without crushing the toner and to cope with high image quality.

As an elastomer which forms an elastic layer, it is preferable to use urethane, acrylonitrile butadiene rubber (NBR), ethylene rubber (EP), silicone rubber (SR), polyamide, or these 2 or more types of elastomers.

Claim 9 of this invention corresponds to this preferable aspect, Comprising: The said transfer belt for image forming apparatuses, The elastomer is urethane, an acrylonitrile butadiene rubber, ethylene rubber, silicone rubber, polyamide, or these 2 or more types of elastomers. It is to provide a transfer belt for an image forming apparatus.

Especially, urethane is especially preferable. Claim 10 of this invention corresponds to this preferable aspect, It is providing the transfer belt for image forming apparatuses as said transfer belt for image forming apparatuses, whose elastomer is urethane.

As described above, when the ion-conducted elastomer is used as the elastomer (form of claim 2), the volume resistivity can be stably controlled, which is preferable. Ion conduction can be performed by dispersing an ion conductive material to make it conductive.

Usually, as a volume resistance value of the whole transfer belt for image forming apparatuses, the range of 10 ^{8-10 14} ohm * cm is preferable. The volume resistivity of the entire transfer belt for an image forming apparatus is the sum of the volume resistivity values of the base layer and the elastic layer. Therefore, by making one side considerably larger than the other and reducing the influence of the other volume resistance value on the volume resistance value of the whole image forming apparatus transfer belt, only one volume resistance value is controlled to control the image transfer apparatus transfer belt. It is also possible to control the total volume resistance value.

The preferred range of the volume resistivity values of the base layer and the elastic layer varies depending on the use form of the transfer belt for the image forming apparatus. In general, however, in the transfer belt for an image forming apparatus, when the resistance value is mainly controlled by the base layer, in-plane unevenness and voltage dependence tend to appear, so it is preferable to control the resistance value by the elastic layer. To do this, the resistance value of the elastic layer may be made larger than the resistance value of the base layer.

The transfer belt for image forming apparatus described above, wherein the transfer belt for image forming apparatus is characterized in that the resistance value (Ω) of the elastic layer is larger than the resistance value (Ω) of the base layer. To provide.

When the resistance value of the elastic layer is expressed in Ω from the viewpoint of controlling the resistance value of the transfer belt for an image forming apparatus more stably and practically, when the resistance value is expressed as Ω, the resistance value of the base layer is 10 times or more, 10 ⁸ It is preferable that it is twice or less.

Claim 12 is, as is intended to preferred for the form, a transfer for the image forming apparatus belt, the resistance of the elastic layer (Ω) is, for more than 10 times the base layer resistance value (Ω) of, 1O characterized in that not more than ⁸ times A transfer belt for an image forming apparatus is provided.

The volume resistivity of the elastic layer is preferably 10 ⁸ to 10 ¹⁴ Ω · cm in consideration of the transfer of the toner.

13. The transfer belt for image forming apparatuses according to claim 13, wherein the volume resistance value of the elastic layer is 10 ⁸ to 10 ¹⁴ Ω · cm, wherein the transfer belt for image forming apparatuses is provided. It is.

The thickness of the elastic layer is preferably in the range of 50 to 300 µm, particularly preferably in the range of 100 to 250 µm, in terms of imparting suitable elasticity (flexibility) in the thickness direction to the transfer belt for the image forming apparatus.

The base layer of the transfer belt for image forming apparatus of the present invention is formed of a material having a high modulus of elasticity and imparts a high tensile modulus of elasticity to the transfer belt for image forming apparatus. Therefore, a material having an elastic modulus of 1 GPa or more is preferable, and more preferably, a material having a modulus of elasticity of 1 to 10 GPa. The volume resistance value of the transfer belt for the image forming apparatus can also be controlled by the material of the base layer.

As a material of high elastic modulus which forms a base layer, polyimide (PI), polyamideimide (PAI), and PVDF are illustrated preferably.

Claim 14 of this invention corresponds to this preferable aspect, The said transfer belt for image forming apparatuses is a base layer formed from polyimide (PI), polyamideimide (PAI), or PVDF. A transfer belt for an image forming apparatus is provided.

A volume resistivity can be controlled by adding a conductive material such as carbon black (acetylene black) to the base layer formed of polyimide (PI), polyamideimide (PAI), PVDF, or the like. Carbon-converted polyimide (PI), carbon-converted polyamideimide (PAI), or carbon-converted PVDF is preferable because it has a high modulus of elasticity.

The thickness of the base layer is preferably in the range of 30 to 100 µm, in particular in terms of imparting a high tensile modulus of elasticity in the circumferential direction of the transfer belt for the image forming apparatus, and particularly in the range of 40 to 80 µm. desirable.

The base layer imparts a tensile modulus in the circumferential direction to the transfer belt for the image forming apparatus, and the elastic layer imparts a ductility in the lamination direction. If the resistance value of the base layer is excessively lowered, the current does not flow in the stacking direction but flows in the circumferential direction, so it is necessary to avoid this. It is preferable to have a suitable relationship with the thickness of a base layer, and the thickness of an elastic layer, and it is preferable that the thickness of an elastic layer is 1-10 times, especially 2-4 times the thickness of a base layer.

The transfer belt for image forming apparatuses, wherein the thickness of the elastic layer is 1 to 10 times the thickness of the base layer, wherein the transfer belt for image forming apparatuses is provided. will be.

In the transfer belt for image forming apparatus of the present invention, a binder layer is preferably formed between the surface layer and the elastic layer. As described above, the binder layer is formed of a material whose melting point is lower than the thermal decomposition point of the material constituting the elastic layer, and the thermal decomposition point is higher than the melting point of the material constituting the surface layer (the form of claim 3). , Especially preferred.

As described above, the binder layer has a melting point equal to or lower than the thermal decomposition point of the material constituting the elastic layer, so that the binder layer and the elastic layer have a melting point higher than that of the binder layer and the elastic layer. By heating the furnace, the binder layer and the elastic layer can be pressed to firmly bond.

Moreover, since the said binder layer is comprised from the material whose thermal decomposition point is the melting point of the material which comprises the said surface layer, it can fuse | melt both by heating to the temperature above the melting point of the said surface layer and below the thermal decomposition point of the said binder layer. have.

By forming such a binder layer, it does not require excessive effort and time, and adhesion | attachment with the fluorine-containing polymer which comprises a surface layer and elastomer, such as urethane which comprises an elastic layer, can be performed. Moreover, since this binder layer does not mix | blend the substance which contaminates a surface layer like a primer, there is also no problem that a contaminant bleeds through a thin surface layer.

It is preferable that the material which forms a binder layer is a material which melt | dissolves in a solvent. That is, the material which comprises the said binder layer can be made to melt only by melt | dissolving in a solvent and apply | coating to the surface layer by the spray method or the dipping method.

Claim 16 corresponds to this preferred aspect, and the transfer belt for image forming apparatus, wherein the material for forming the binder layer is a material dissolved in a solvent, to provide a transfer belt for image forming apparatus. .

It is preferable that the binder layer is a fluorine-containing polymer, and among them, since it contains a tetrafluoride component, it is easy to adhere to PTFE and PFA, and has a grade having a low melting point of 110 ° C, and a decomposition point of 400 ° C It is preferable that it is THV for reasons of high melting point), excellent adhesiveness with urethane, etc., and softness. It is preferable that especially a binder layer is THV and a surface layer is PTFE or PFA.

Claim 17 corresponds to this preferred aspect, and provides a transfer belt for an image forming apparatus, wherein said binder layer is THV as said transfer belt for image forming apparatus.

As described above, the fluorine-containing polymer used as the surface layer of the transfer belt for the image forming apparatus of the present invention is excellent in peeling toner. When such a fluorine-containing polymer is used for the surface layer, the binder layer is also formed of the fluorine-containing polymer, whereby the adhesion of both layers is sufficiently strong. Moreover, the adhesive force of both layers can be heightened more by adding the same fluorine-containing polymer as the fluorine-containing polymer which forms a surface layer to the polymer of a binder layer. According to this method, even if the binder layer is not formed of a fluorine-containing polymer, adhesion with the surface layer is possible.

The fluorine-containing polymer to be contained in the binder layer is preferably in the form of a powder and contained in the material forming the binder layer. In this case, the particle diameter of the powdery product is preferably 0.1 to 10 mu m. This is because powder-like articles having a particle diameter of less than 0.1 mu m are difficult to manufacture, while if the particle diameter exceeds 10 mu m, problems of sedimentation are likely to occur, and surface roughness tends to deteriorate.

Next, when the amount of the fluorine-containing polymer contained in the binder layer is too small, the effect of sufficient adhesive strength cannot be obtained. On the other hand, when the amount of the fluorine-containing polymer is excessively large, the influence on properties such as THV, which is the main constituent material of the binder layer, becomes large. The preferable quantity of the fluorine-containing polymer contained in the binder layer which considered the above is 1-300 parts with respect to 100 parts of materials which form a binder layer. In particular, when the surface layer is formed of PFA and the binder layer is formed of THV, it is preferable that 10 to 100 parts of PFA is contained in THV.

The transfer belt for image forming apparatuses according to claim 18, wherein the transfer belt for image forming apparatuses comprises a fluorine-containing polymer for forming a surface layer in a binder layer. It is.

When the thickness of the binder layer becomes thick, the volume resistivity rises, and when it becomes thin, the adhesive strength decreases. From such a viewpoint, it is preferable that it is 0.1-10 micrometers.

Claim 20 corresponds to this preferred aspect, and provides a transfer belt for an image forming apparatus, wherein the thickness of the binder layer is 0.1 to 10 mu m as said transfer belt for image forming apparatus.

The present invention is not limited to a transfer belt for an image forming apparatus comprising only a base layer, an elastic layer, a binder layer, and a surface layer, and depending on the required characteristics, the base layer and The structure in which the other layer which is not prescribed | regulated in this specification is formed between an elastic layer, between an elastic layer and a binder layer, and between a binder layer and a surface layer is included.

The transfer belt of the present invention is for an image forming apparatus and has a function of transferring a toner image formed on a photosensitive drum or the like to a transfer material such as paper. Here, examples of the image forming apparatus include a copier, a laser printer, and the like using an electrophotographic method, but the present invention is not limited thereto, and has a function of forming an image on a transfer material by forming a toner image and transferring it to a transfer material. Includes all of the devices.

The transfer belt for an image forming apparatus of the present invention also includes a transfer fixing belt for an image forming apparatus that simultaneously performs transfer and fixing. In particular, the present invention is applied to such a transfer belt for an image forming apparatus in view of efficiency. It is preferable.

Claim 21 of this invention corresponds to this preferable aspect, The said transfer belt for image forming apparatuses, The transfer belt for image forming apparatuses is the transfer belt for image forming apparatuses characterized by the above-mentioned. To provide.

In the transfer belt for an image forming apparatus of the present invention, since a surface layer formed of a fluorine-containing polymer is used, large surface resistivity, excellent peeling toner property, and excellent non-pollution property can be achieved.

In recent years, development of toners capable of coping with colorization and high image quality of image forming apparatuses has been actively progressed, and among these, many of them have insufficient release property and contamination resistance, and image forming apparatuses which are conventional monolayers such as polyimide and polyamideimide. In the transfer belt for the image forming apparatus and the transfer belt for the image forming apparatus which is spray-coated with urethane, silicone, etc., it could not fully respond to these. However, according to the present invention, the transfer belt for the image forming apparatus can be obtained sufficiently.

In particular, when a specific one such as PTFE or PFA is used as the fluorine-containing polymer, the surface resistivity, peeling toner property, and non-pollution property are particularly excellent.

In addition, when certain fluorine-containing polymers, such as PVDF and THV, are used, they are excellent in surface resistivity, peeling toner property, non-pollution property, etc., and are easily processed to further improve the properties of the transfer belt for an image forming apparatus. You can also get benefits such as.

Further, by using polyamide, polyamideimide or PVDF as the base layer, a transfer belt for an image forming apparatus having a high tensile strength in the circumferential direction can be obtained.

Further, the transfer belt for image forming apparatus of the present invention has a sufficient flexibility in the thickness direction because an elastic layer formed of an elastomer is formed between the base layer and the surface layer.

In addition, when an ion-conducted elastomer (form of claim 2) is used as the elastomer forming the elastic layer, the volume resistivity can be controlled more stably.

When the resistance value of the elastic layer is larger than the resistance value of the base layer, only the elastic layer can control the resistance value of which the transfer belt for image forming apparatus is stable.

In addition, when a binder layer is formed between the surface layer and the elastic layer whose melting point is less than or equal to the thermal decomposition point of the material constituting the elastic layer, and the thermal decomposition point is formed by the material having the melting point or higher than the material constituting the surface layer. Can perform adhesion of a surface layer and an elastic layer, without requiring excessive effort and time. Moreover, since this binder layer does not mix | blend the substance which contaminates a surface layer like a primer, there is no problem that a contaminant bleeds through a thin surface layer.

1 is a cross-sectional view showing an example of a transfer belt for an image forming apparatus of the present invention. The transfer belt for the image forming apparatus of FIG. 1 has an elastic layer 12 between the surface layer 9 and the base layer 11, and the surface layer 9 and the base layer 11. The surface layer 9 is formed of PTFE, and as a result, excellent peeling toner property can be obtained.

The base layer 11 is formed of polyimide within the range of 1-10 GPa of elastic modulus, The thickness is in the range of 40-80 micrometers. As a result, a high tensile modulus in the circumferential direction of the transfer belt for the image forming apparatus is given to the transfer belt for the image forming apparatus.

The elastic layer 12 is formed of aqueous urethane. The thickness of the elastic layer 12 is in the range of 100 to 250 µm, and as a result, proper flexibility in the thickness direction is given to the transfer belt for the image forming apparatus.

The elastic layer 12 has a volume resistance value in the range of 10 ⁸ to 10 ¹⁴ Ω · cm. In addition, the volume resistivity of the elastic layer 12 is 10 times or more of the volume resistivity of the base layer 11, and therefore the volume resistivity of the entire transfer belt for the image forming apparatus is also within the range of 10 ⁸ to 10 ¹⁴ Ω · cm. to be.

Although an Example is shown below, the scope of the present invention is not limited to the following Example. Within the same and equivalent ranges as the present invention, it is possible to add various modifications to the following examples.

Example 1

The polyimide layer (base layer) of 60 micrometers in thickness which coats the circumference | surroundings of a metal mold | die, apply | coats a polyimide varnish to the outer side, rotating a drum-shaped metal mold | die, and then heats a metal mold | die and performs imidation reaction. Formed. Next, a thickener was added to the aqueous urethane to a viscosity of about 1 OPa · s, and defoaming was carried out, followed by dipping on the polyimide layer. After application, moisture was dried at a constant temperature, and then annealed again at 160 ° C. to form a urethane layer (elastic layer) having a thickness of 200 μm on the polyimide layer.

Next, the solution of THV was spray-coated on the said urethane layer on condition that the thickness after drying and annealing becomes 5 micrometers. Then, drying and annealing at 160 degreeC were performed, the surface layer was formed and the transfer belt of this invention was obtained.

Example 2

First, as shown in Fig. 2, PTFE (melting point 327 DEG C, thermal decomposition point 400 DEG C) was applied to the inner surface of an outer cylinder 8 made of steel having a coefficient of thermal expansion 1.76 x 10 ^-5 / deg. Dispersion was apply | coated by the dipping method, it baked at 380 degreeC, and the surface layer 9 was formed.

Furthermore, THV (melting point 120 degreeC, thermal decomposition point 400 degreeC) was melted in butyl acetate, it formed into a film by the dipping method on the surface layer 9, it dried, and the binder layer 14 was formed. In addition, the binder layer 14 was heated at 350 degreeC above melting | fusing point of PTFE and THV, and was made to adhere to the surface layer 9.

Next, as shown in FIG. 3, carbon conduction treatment is performed by adding acetylene black to the surface of the drum-shaped mold 10 to form a polyimide having a volume resistance adjusted, and baked at 380 ° C. Layer 11 was formed.

On the base layer 11, an aqueous urethane (melting point 120 DEG C, thermal decomposition point 180 DEG C) was applied by a dipping method and dried to form an elastic layer 12.

Next, the composite of the base layer 11 and the elastic layer 12 formed on the surface of the drum-shaped mold 10 is peeled from the drum-shaped mold 10, and the composite formed in a cylindrical shape is shown in FIG. Similarly, it fits in the outer periphery of the middle element 13 made from MC nylon of thermal expansion coefficient 8.Ox10 <^-5> / degreeC.

Next, as shown in FIG. 5, the core 13 in which the composite of the base layer 11 and the elastic layer 12 is sandwiched is formed, and the composite layer of the binder layer 14 and the surface layer 9 is formed on the inner surface. It inserted into the outer cylinder 8, and it heated at 150 degreeC in vacuum. Due to this heating, the coefficient of thermal expansion of the outer cylinder 8 and the core 13 is different, so that the thermally expanded core 13 presses the inner surface of the outer cylinder 8, and the base layer 11 The composite of the four-layer structure which consists of the composite layer of the elastic layer 12, and the composite layer of the binder layer 14 and the surface layer 9 was obtained. The cross section of this composite is shown in FIG.

Next, the core 13 and the outer cylinder 8 were cooled, and the four-layered composite was separated therefrom to obtain a transfer belt for an image forming apparatus.

The obtained transfer belt for an image forming apparatus is formed on a base layer (polyimide) having a thickness of 60 μm, an elastic layer (urethane) having a thickness of 200 μm, a binder layer (THV) having a thickness of 1 μm, and a surface layer having a thickness of 5 μm (PTFE). ) Is a transfer belt for an image forming apparatus having excellent surface resistivity, peeling toner property, and non-pollution property.

Although melting | fusing point of THV which is a binder layer used in this Example is 120 degreeC, melting | fusing point of PTFE of surface layer is 327 degreeC. Therefore, in the method of forming an elastic layer, a binder layer, and a surface layer sequentially from a base layer using a spray method, it is difficult to bake a surface layer. However, the elastic layer and the binder layer could be firmly adhered by the above manufacturing method, that is, by pressing the inner surface of the outer cylinder 8 by the core 13.

In addition, in the said Example, the inner surface of the outer cylinder 8 was pressed by the core 13, the composite layer of the base layer 11 and the elastic layer 12, the binder layer 14, and the surface layer ( As a method of obtaining a composite with the composite layer of 9), the difference in thermal expansion coefficient between the core 13 and the outer cylinder 8 was used, but another method, for example, using an instantaneous explosive force using air pressure or the like. By this, the composite of the base layer 11 and the elastic layer 12 may be pressed against the composite layer of the binder layer 14 and the surface layer 9 to obtain a transfer belt for the image forming apparatus.

Example 3

The thickness of the binder layer 14 was changed by changing the amount of THV melted in butyl acetate, and the water-based urethane applied on the base layer 11 was changed to that in which the ion conductive treatment was performed. Similarly, image formation having an elastic layer (urethane) having a thickness of 200 µm, a binder layer (THV) having a thickness of 3 µm, and a surface layer (PTFE) having a thickness of 5 µm on a base layer (polyimide) having a thickness of 60 µm. A transfer belt for the device was obtained. The ion conductive treatment was performed by dispersing the ion conductive agent in the aqueous urethane, so that the volume resistivity was adjusted to 10 times the volume resistivity of the base layer 11.

The obtained transfer belt for image forming apparatus was excellent in all of surface resistivity, peeling toner property and non-pollution property. The volume resistivity of the transfer belt for the image forming apparatus was stably controlled by the elastic layer 12. In addition, between the surface layer and the binder layer, between the binder layer and the elastic layer is firmly adhered, and bleeding did not occur.

Example 4

As the dispersion of PTFE used for the formation of the surface layer 9, the aqueous urethane to be applied on the base layer 11 was dispersed except that ion conduction treatment was carried out using a dispersion of conductive zinc oxide (ZnO). In the same manner as in Example 2, on the base layer (polyimide) having a thickness of 60 μm, an elastic layer (urethane) having a thickness of 200 μm, a binder layer (THV) having a thickness of 1 μm, and a surface layer having a thickness of 5 μm (PTFE) ), A transfer belt for an image forming apparatus was obtained.

The ion conductive treatment was performed by dispersing the ion conductive agent in the aqueous urethane to adjust the volume resistivity to 10 ⁹ Ω · cm. The volume resistivity of the surface layer 9 is 10 ¹¹ Ω · cm, the volume resistivity of the binder layer 14 is 10 ¹⁰ Ω · cm, and the polyimide forming the base layer 11 has a volume resistivity due to carbon conduction treatment. It was adjusted to 10 ⁸ Ω · cm.

The obtained transfer belt for image forming apparatus was excellent in all of surface resistivity, peeling toner property and non-pollution property. The volume resistivity of the transfer belt for the image forming apparatus was stably controlled by the elastic layer 12.

Example 5

As shown in Fig. 2, PFA (DuPont 350J dispersion, particle size 0.2 mu m) (melting point) was formed on the inner surface of the outer cylinder 8 made of steel having a coefficient of thermal expansion of 1.76 × 10 ⁻⁵ / ° C. 295 degreeC) was apply | coated by the dipping method, it baked at 380 degreeC, and the surface layer 9 was formed.

Further, THV (THV220 manufactured by Sumitomo 3M Co., Ltd.) (melting point 120 ° C., thermal decomposition point 400 ° C.) is melted in butyl acetate, and formed on the surface layer 9 by a dipping method, dried to form a binder layer 14. It was. Moreover, the binder layer 14 was heated at 350 degreeC of melting | fusing point of PFA and THV, and was made to adhere to the surface layer 9. A transfer belt for an image forming apparatus was obtained in the same manner as in Example 3 except for the above.

The obtained transfer belt for image forming apparatus was formed on a base layer (polyimide) having a thickness of 60 µm, an elastic layer (urethane) having a thickness of 200 µm, a binder layer (THV) having a thickness of 3 µm, and a thickness of 5 µm. A transfer belt for an image forming apparatus having a phosphorus surface layer (PFA), and excellent in surface resistivity, peeling toner property, and non-pollution property, was obtained.

The volume resistivity of the transfer belt for the image forming apparatus was stably controlled by the elastic layer 12. In addition, between the surface layer and the binder layer, between the binder layer and the elastic layer is firmly adhered, bleeding did not occur.

Moreover, although melting | fusing point of THV of a binder layer is 120 degreeC, since melting | fusing point of PFA of a surface layer is 295 degreeC, in the method of forming an elastic layer, a binder layer, and a surface layer sequentially from a base layer using a spraying method, Although it is difficult to bake the surface layer, it was possible to firmly bond the elastic layer and the binder layer by the above production method.

Example 6

At the time of forming the binder layer, 60 parts in advance of a powdery substance of PFA (340J manufactured by Dupont, 0.2 µm in particle size) forming a surface layer in THV (THV220 manufactured by Sumitomo 3M) was added to THV 100 parts in advance, and THV was added. It was melted in butyl acetate. A transfer belt for an image forming apparatus was obtained in the same manner as in Example 5 except for the above.

The obtained transfer belt for image forming apparatus was formed on a base layer (polyimide) having a thickness of 60 µm, an elastic layer (urethane) having a thickness of 200 µm, a binder layer (THV) having a thickness of 3 µm, and a thickness of 5 µm. A transfer belt for an image forming apparatus having a phosphorus surface layer (PFA), and excellent in surface resistivity, peeling toner property, and non-pollution property, was obtained.

Next, the adhesion between the surface layer and the binder layer of the transfer belt for image forming apparatus obtained in Example 3, Example 5 or Example 6 was measured. The measurement was performed by the following method. That is, in the measurement point formed by cut | disconnecting the 1 cm width sheath in the surface layer and the binder layer, the force required in order to peel both layers was measured as adhesive force.

As a result of the measurement, in the case of Example 3 and Example 5, the adhesive force was 0.06 kg / cm, but in Example 6, it was 0.35 kg / cm. From the above results, it was confirmed that the adhesive force between the surface layer and the binder layer was improved by containing the fluorine-containing polymer forming the surface layer in the binder layer.

According to the present invention, it has a larger surface resistivity, excellent peeling toner property, excellent non-pollution property, stable volume resistance, and the like, and there is no possibility of bleeding of contaminants, and also excellent adhesion between the surface layer and the elastic layer The transferred belt for the image forming apparatus can be manufactured without requiring excessive effort and time.

Claims (21)

On the base layer, An elastic layer having an elastomer, Surface layer formed by fluorine-containing polymer Transfer belt for an image forming apparatus having a. The method of claim 1, And the elastic layer is formed of an ion-conducted elastomer. The method according to claim 1 or 2, A binder layer is provided between the elastic layer and the surface layer, and the binder layer has a melting point that is lower than the thermal decomposition point of the material constituting the elastic layer, and the thermal decomposition point is higher than the melting point of the material constituting the surface layer. A transfer belt for an image forming apparatus, characterized in that formed by. The method according to any one of claims 1 to 3, A transfer belt for an image forming apparatus, wherein the fluorine-containing polymer is polytetrafluoroethylene (PTFE) or tetrafluoroethylene perfluoroalkyl vinyl ether (PFA). The method according to any one of claims 1 to 3, A transfer belt for an image forming apparatus, wherein the fluorine-containing polymer is a polymer of a monomer containing vinylidene fluoride. The method of claim 5, A transfer belt for an image forming apparatus, wherein the fluorine-containing polymer is polyvinylidene fluoride (PVDF). The method of claim 5, A transfer belt for an image forming apparatus, wherein the fluorine-containing polymer is a copolymer (THV) of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride. The method of claim 5, The fluorine-containing polymer is a copolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride (THV) or polyvinylidene fluoride (PVDF), the elastic layer is urethane, and the surface layer is a solution of THV or PVDF. The transfer belt for the image forming apparatus, characterized in that formed by spray coating on the elastic layer. The method according to any one of claims 1 to 8, The transfer belt for an image forming apparatus, wherein the elastomer is urethane, acrylonitrile butadiene rubber, ethylene rubber, silicone rubber, polyamide, or two or more kinds of these elastomers. The method of claim 9, The transfer belt for image forming apparatus, wherein the elastomer is urethane. The method according to any one of claims 1 to 10, A transfer belt for an image forming apparatus, wherein the resistance value (Ω) of the elastic layer is larger than the resistance value (Ω) of the base layer. The method of claim 11, The resistance value (Ω) of the elastic layer, the transfer belt for an image forming apparatus, characterized in that less than 1O times, 1O ⁸ times the base layer resistance value (Ω) of the. The method according to any one of claims 1 to 12, A transfer belt for an image forming apparatus, wherein the volume resistivity of the elastic layer is 10 ⁸ to 10 ¹⁴ Ω · cm. The method according to any one of claims 1 to 13, A transfer belt for an image forming apparatus, wherein the base layer is formed of polyimide (PI), polyamideimide (PAI), or polyvinylidene fluoride (PVDF). The method according to any one of claims 1 to 14, The transfer belt for image forming apparatus, wherein the thickness of the elastic layer is 1 to 10 times the thickness of the base layer. The method of claim 3, wherein A transfer belt for an image forming apparatus, wherein the material for forming the binder layer is a material dissolved in a solvent. The method according to claim 3 or 16, A transfer belt for an image forming apparatus, wherein the binder layer is a copolymer (THV) of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride. The method according to claim 3, 16 or 17, A transfer belt for an image forming apparatus, wherein a binder layer contains a fluorine-containing polymer for forming a surface layer. The method according to any one of claims 1 to 18, The thickness of the surface layer is 1-15 micrometers, The transfer belt for image forming apparatuses characterized by the above-mentioned. The method according to any one of claims 1 to 19, The thickness of the binder layer is 0.1 to 10 micrometers, The transfer belt for image forming apparatuses characterized by the above-mentioned. The method according to any one of claims 1 to 20, A transfer belt for an image forming apparatus is a transfer fixing belt for an image forming apparatus.